The Isotopic Composition of Precambrian Sulphides—Seawater Chemistry and Biological Evolution

  1. Wladyslaw Altermann2 and
  2. Patricia L. Corcoran3
  1. H. Strauss

Published Online: 12 MAR 2009

DOI: 10.1002/9781444304312.ch4

Precambrian Sedimentary Environments: A Modern Approach to Ancient Depositional Systems

Precambrian Sedimentary Environments: A Modern Approach to Ancient Depositional Systems

How to Cite

Strauss, H. (2002) The Isotopic Composition of Precambrian Sulphides—Seawater Chemistry and Biological Evolution, in Precambrian Sedimentary Environments: A Modern Approach to Ancient Depositional Systems (eds W. Altermann and P. L. Corcoran), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444304312.ch4

Editor Information

  1. 2

    Institut für Allgemeine und Angewandte Geologie, Ludwig-Maximilians-Universität München, Luisenstrasse 37, D-80333 Munich, Germany

  2. 3

    Department of Earth Sciences, Dalhousie University, Halifax, Nova Scotia, B3H 3J5, Canada

Author Information

  1. Institut für Geologie, Ruhr-Universität Bochum, Universitätsstrasse 150, 44801 Bochum, Germany

Publication History

  1. Published Online: 12 MAR 2009
  2. Published Print: 18 FEB 2002

ISBN Information

Print ISBN: 9780632064151

Online ISBN: 9781444304312

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Keywords:

  • isotopic composition of precambrian sulphides-seawater chemistry and biological evolution;
  • isotopic biogeochemistry of modern marine sediments;
  • sulphur isotope systematics and analytical methods;
  • biogeochemistry of archaean sedimentary systems - integral part in unravelling evolution of life on earth;
  • archaean–proterozoic transition;
  • palaeoproterozoic and mesoproterozoic;
  • neoproterozoic and its transition into early palaeozoic;
  • temporal evolution of biological sulphur cycle during precambrian times;
  • neoproterozoic recording major changes in sedimentary sulphur cycle

Summary

The sulphur isotopic composition of sedimentary sulphides records the temporal evolution of the Precambrian sulphur cycle. Early Archaean sediments show δ34S values for pyrite around 0‰ and are interpreted to reflect a predominantly magmatic origin for sedimentary pyrite. Pyrite in sediments across the Archaean–Proterozoic transition record a substantial variability in δ34S that resembles modern style bacterial sulphate reduction. During Proterozoic time, bacterial sulphate reduction, although in principle organic carbon limited, also appears to be characterized by sulphate limitation as evident from frequently positive sulphur isotope values. This is attributed to effective sulphate turnover as a consequence of readily metabolizable organic matter and possibly a lower sulphate concentration in the ocean. Based on distinct distributions of δ34S values for sedimentary pyrite, the Neoproterozoic sulphur cycle appears to have responded to perturbations of the global ocean/atmosphere system as a consequence of repeated glaciations and resulting biogeochemical changes. This is consistent with the proposed Snowball Earth concept. Interpretations of the Precambrian sedimentary sulphur cycle result from a systematic assessment of organic carbon, sulphide sulphur and reactive iron abundances, 334 new and several hundred previously published sulphur isotope values for sedimentary pyrite and a comparison to the isotopic composition of Precambrian seawater sulphate as evident from marine evaporites.